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Products > Combined Cycle > GT MASTER > Sample 1

Net Dependable Capacity of a 350 MW Condensing Combined Cycle with Cogeneration

Whereas in GT PRO you often create many different designs for a single project when you are scoping out various options, in GT MASTER, you want to run many different operational scenarios using a single plant configuration.  This sample focuses on using a single plant model to compute expected performance under different ambient situations.

This is a model of a three pressure non-reheat combined cycle in 2-on-1 configuration with cogeneration steam taken from IP header.  The plant uses two ALSTOM GT 11N2 gas turbines, nominally rated at 115.4 MW, 865 lb/s / 392 kg/s airflow, 33.6% LHV efficiency and 988 F / 531 C exhaust temperature.  Nominal ISO net plant performance is 344 MW electric output at 50.6% LHV efficiency (6740 BTU/kWhr LHV heat rate) with no process steam flow.

The E-LINK utility lets you run batches of cases from MS Excel.  The plant design here is used to generate expected performance plots shown below using E-LINK.

This chart shows the net dependable capacity map over a range of site temperatures and process extraction flows with gas turbine at full load, and duct burner off.  This plant, unfired, produces from 267 to 367 MW over the full extent of expected ambient temperatures and process flows.

The companion chart below shows the net LHV heat rate map at the same conditions.  The heat rate is predicted to vary by almost 20% in this range of conditions, although at a given steam its variation with ambient changes is considerably less.